You'd probably need a much bigger sample than the five games I used to say for certain. Even in the small sample I used, there was an oddity. A Spot of Bother was originally 110kb under v4 and 163kb under v5 (an increase of 53kb) whereas Cowboy Blues went from 109kb under v4 to 154kb under v5 (an increase of just 45kb). For two games which were originally very, very close to the same size under v4 (just 1kb difference, which works out at a few hundred words), you'd expect them to be roughly the same size under v5, yet one was 9kb bigger than the other.